Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare the safe read-only profile (readOnlyHint=true, destructiveHint=false), so the bar is lower. The description adds genuine behavioral context beyond them: a parsing cap of 50 blocks, no auth/cost requirement, and that source and input limits apply. It stops short of a 5 because the referenced 'limits' are left vague.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Four short sentences with the purpose front-loaded and no wasted preamble. There is mild redundancy: 'FREE during validation' and 'No key, credits or wallet' both convey the same cost-free point, which slightly dilutes tightness.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists, so return values need no explanation, and annotations carry the safety profile. The description covers purpose, the 50-block cap, and the free/no-auth model, which is close to complete for a parse tool. The unspecified 'input limits' leaves a minor gap.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 67%, and the schema already documents requestId and maxPriceMicroUsd as 'ignored in free mode.' The description adds nothing about the required input.html beyond loosely gesturing at 'supplied HTML' and 'input limits.' Baseline 3 is appropriate since the schema does the substantive work.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource with scope: 'Parse up to 50 JSON-LD blocks from supplied HTML.' The resource (JSON-LD) is specific enough to distinguish it from sibling html_* tools like html_metadata and html_links. It doesn't explicitly name a sibling it differs from, so it falls short of a 5.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description offers no when-to-use guidance or alternatives; it never says when to reach for html_jsonld over html_metadata or html_main_text. The 'FREE during validation' and 'No key, credits or wallet' lines are cost/pricing notes, not usage guidance. The agent is left to infer context.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.